• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.3B
• /
• pp.339-348
• /
• 2004

Packet classification is an important factor to support various services such as QoS guarantee and VPN for users in Internet. Packet classification is a searching process for best matching rule on rule tables by employing multi-field such as source address, protocol, and port number as well as destination address in If header. In this paper, we propose hardware based packet classification algorithm by employing tree bitmap of multi-bit trio. We divided prefixes of searching fields and rule into multi-bit stride, and perform a rule searching with multi-bit of fixed size. The proposed scheme can reduce the access times taking for rule search by employing indexing key in a fixed size of upper bits of rule prefixes. We also employ a marker prefixes in order to remove backtracking during searching a rule. In this paper, we generate two dimensional random rule set of source address and destination address using routing tables provided by IPMA Project, and compare its memory usages and performance.

• The Journal of the Korea Contents Association
• /
• v.12 no.12
• /
• pp.46-53
• /
• 2012

The traffic in research network for the new structure of the network and new service research has the various properties. From the perspective of a specific traffic point of view, transmission of traffic with different requirements using a single routing protocol is an obstacle to satisfy requirements. In this study, we classify the properties of the traffic into two types. We propose the way that we can get the overall optimization effect, the experiment proves it by providing independent multiple forwarding path by applying optimized algorithm by types. In order to distinguish each type of traffic we use the ports on the switch and in order to implement independent path we apply OpenFlow system. In other words, we present the measure that can be implemented to improve the satisfaction of the traffic by making multiple paths by OpenFlow controller according to the type of traffic and by enforcing in Forwarder.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.10
• /
• pp.21-29
• /
• 2013

This paper proposed the architecture of the authentication and the transmission for high reliable emergency data management based on U-healthcare wireless mesh networks. In U-healthcare monitoring service, the high reliable bio data management as well as the data transmission are required because the monitoring emergency bio data is related linked to life. More specifically, the technologies of the identity authentication of the measuring bio data, the personalized emergency status diagnosis who is authenticated the bio data and the emergency data transmission are important first of all. To do this, this paper presents the structure and protocol of the identity authentication management with using the extended IEEE 11073 PHD, the structure of policy-based management of the emergency bio data for the highly reliable management and the resilient routing protocol based on wireless mesh network for the reliable data transmission.

• The Journal of the Korea Contents Association
• /
• v.13 no.2
• /
• pp.44-51
• /
• 2013

Routers should perform fast IP address lookup for Internet to provide high-speed service. In this paper, we present a hybrid parallel IP address lookup structure composed of four-stage pipeline. It achieves parallelism at low cost by using multiple SRAMs in stage 2 and partitioned TCAMs in stage 3, and improves the performance through pipelining. The smart distributor in stage 1 does not transfer any IP address identical to previous one toward the next stage, but only uses the result of the previous lookup. So it improves throughput of lookup by caching effects, and decreases the access conflict to TCAM bank in stage 3 as well. In the last stage, the reorder buffer rearranges the completed IP addresses according to the input order. We evaluate the performance of our parallel pipelined IP lookup structure comparing with previous hybrid structure, using the real routing table and traffic distributions generated by Zipf's law.

• Journal of Korea Multimedia Society
• /
• v.16 no.9
• /
• pp.1077-1088
• /
• 2013

As broadcasting is the process that a node sends a packet to all nodes in the network. it is basic process used for discovering of a routes to a node and disseminating of control information message in Mobile Ad hoc NETwork (MANET). In this paper, we propose dynamically adjusted probabilistic mechanism based on distance ratio and node density for broadcasting in MANETs. The distance ratio can be calculated as the ratio of the radio strength length to the distance from sender of a node, and node density can be get from 1-hop nodes of neighbours. A mobile node receiving broadcast packets determines the probability of rebroadcasting considering distance ratio and node density of itself. Rebroadcast probability will be set as low value to a node which is located in nearby area of sender and has high 1-hop node density, So it reduces packets transmission caused by the early die-out of rebroadcast packets. Compared with the simple flooding and fixed probabilistic flooding by simulation, our approach shows better performances results. Proposed algorithm can reduce the rebroadcast packet delivery more than 30% without scanting reachability, where as it shows up to 96% reachability compared with flooding.

• Journal of Advanced Navigation Technology
• /
• v.18 no.6
• /
• pp.594-599
• /
• 2014

The routinized wireless devices such as smart phone have promoted to expand the use of IEEE 802.11 groups. The challenge environments of the wireless network utilizes effectively and user-oriented seamless services that handover is the most desirable issues under the wireless circumstance. In data center software defined network (SDN) has provided the flow routing to reduce costs and complexities. Flow routing has directly offered control for network administrator and has given to reduce delay for users. Under the circumstance of being short of network facilities, SDNs give the virtualization of network environments and to support out of the isolation traffic conditions. It shows that the mechanism of handover makes sure seamless services for higher density of the network infrastructure which is SDN to support network service re-configurable.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.8 no.3
• /
• pp.541-548
• /
• 2007

The workflow, one of core features for modern business operation, models common elements and their relationships in business processes. The research is focused on how to adapt the workflow model to the healthcare examination which becomes popular these days. Especially, we intend to have fully automated process for healthcare examination by providing customers with PDA with RFTD chip. In order to realize this goal, this paper proposes the design of software architectures the class structures, and the definition of messages used for the system interactions. In other word, the paper shows the analysis of healthcare application in terms of service scenario and the design of workflow engine ant ubiquitous healthcare application under the Object-Oriented programming environment. the The result of the study may also enable the unmanned healthcare examination as well as ubiquitous based healcare examination sooner or later.

• The KIPS Transactions:PartC
• /
• v.9C no.4
• /
• pp.589-596
• /
• 2002

Tn the data transmission service of the mobile host, it is needed to reduce the bandwidth and to make a reliable error recovery. there are two appropriate methods in that. One is FEC which retransmits the parity of error recovery, in case of happening of the loss after forming the parity of error recovery by grouping original data. The other is local recovery based on server which can block the implosion of transmission. The use of FEC and local recovery based on server at the same time enables the reliable multicast. This paper suggests algorithm that recovers the loss by FEC and local recovery based on server through the solution of the problems about triangle routing, tunnel convergence by dividing mobile host into two parts-the sender and the receiver. This model about the loss of algorithm tested the efficiency of performance by the homogeneous independent loss, the heterogeneous independent loss, the shared source link loss model. The suggested algorithm confirms effectiveness in the environment where there are much data and many receivers in mobile host.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.3A
• /
• pp.287-295
• /
• 2010

In wireless sensor networks(WSNs), the studies that support sink mobility without global position information exploit a Backbone-based Virtual Infrastructure (BVI) which considers one-hop clusters and a backbone-based tree. Since the clusters of a sink and a source node are connected via flooding into the infrastructure, it causes high routing cost. Although the network could reduce the number of clusters via multi-level clusters, if the source nodes exist at nearest clusters from the cluster attached by the sink and they are in different branches of the tree, the data should be delivered via detour paths on the tree. Therefore, to reduce the number of clusters, we propose a novel multi-hop cluster based communication protocol supporting sink mobility without global position information. We exploit a rendezvous cluster head for sink location service and data dissemination but the proposed protocol effectively reduces data detour via comparing cluster hops from the source. Simulation shows that the proposed protocol is superior to the existing protocols in terms of the data delivery hop counts.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.48 no.4
• /
• pp.295-301
• /
• 2020

When a spacecraft in deep space falls into an abnormal state, an emergency communication channel between ground and the spacecraft is essential in order to perform analysis to the cause of the anomaly, and to remedy the spacecraft from the distressed state. Because the recovery actions generally comprises of long and complicated sequences of commands, the transmission of the recovery commands may require a reliable and a delay tolerant networking technology based on bundle routing. While the delay tolerant networking protocol becomes a prominent method interfacing ground and space into a internet-like Solar system network because it can address the issues of the severe communication problems in deep space, the communication system on the spacecraft which based on space packet protocol cannot use the delay tolerant networking technology directly. So a community of the consultative committee for space data systems starts a discussion of the first-hop last-hop mechanism to establish a feasible concept and standardization. This paper presents an enhanced concept of the first-hop last-hop by applying it a virtual cislunar communication environment, and we believe this contributes to make a way applicable to an interoperable relay concept of the first hop last hop between the delay tolerant networking and space packet protocol standard.